Every home, office, apartment, and hotel room has at least one door that separates the interior from the outside world. Many of these doors provide a peephole in the door to allow a person on the inside to securely see through the door without being seen by anyone on the other side.
Conventional peepholes are impossible to use unless a person is actually standing at the door to look through the peephole. Enhancement devices have been created to record images through the peephole, but the user must still interact with the device in order to access the images.
With the worldwide explosion of cell phone ownership, people are much more connected and are used to being instantly informed of events that occur that affect their lives. If a cell phone owner misses a call, the expectation is that the caller will leave a message. Even if that does not happen, the missed call is recorded in a log and can be reviewed by the phone owner at a later time.
Wireless networking technology is also relatively ubiquitous in modern life and allows devices to transmit and receive data without physical connections.